Carbon dioxide and water vapor are commonly found in the exhaust emitted from many industrial processes such as fossil fuel power plants, including those using conventional pulverized coal, integrated gasification combined cycles (IGCC), natural gas combined cycles, chemical looping, and fossil oil-based fuels. Currently, these gases are typically simply vented to the atmosphere. However, due to recent widespread environmental concern and developing and expected regulatory mandates, it is desirable to minimize atmospheric carbon dioxide emissions.
One proposed method of reducing carbon dioxide emissions involves carbon dioxide capture and, optionally, sequestration. In order to effectively and safely sequester carbon dioxide by many current and proposed techniques, however, relatively high purities are required. Moreover, from the standpoint of overall water usage for many of the above mentioned processes, for both economic and environmental reasons, the ability to recover water at relatively high purity from exhaust streams including carbon dioxide/water mixtures is also desirable. Various techniques have been proposed for the separation of carbon dioxide from water including, for example, organic solvent-based absorption, selective membrane separation, and vapor condensation at low pressures. However, these techniques may pose disadvantages. For example, organic solvent-based methods often make use of expensive and/or toxic solvents. In addition, many of the above-mentioned methods require use of expensive, specialized equipment and/or are energy intensive, leading to large parasitic loads on power generating systems to which they are applied.
Accordingly, improved systems and methods for the separation of carbon dioxide from water are desirable.